The invention is a device for upsetting, especially on presses, consisting of two rigid structures, one of which forms the frame, the other the head of the device, and of at least one split tool holder containing die inserts clamping the workpiece and upsetting it in the upsetting zone, located in front of the face of the split dies. One side of the split die holder is slidingly supported by one of the rigid structures in a plane parallel to the split die parting plane while the other side is supported by the parallelogram linkage mechanism, made of at least two toggles which mechanism is, in turn, supported by the other rigid structure of the device. The toggles are kinematically coupled to links, borne on both ends, maintaining the assumed distance of the axes of the two joints of each toggle.
Structures of this kind are known, e.g. from the Polish patent description no. 123785 or U.S. Pat. No. 3,348,407.
They enable conversion of the vertical force of the press slide or other mover to the horizontal force upsetting the workpiece while the vertical component of the press force results in self clamping the workpiece in the split dies. The device reveals the following drawbacks:
1. It has too big overall dimensions in relation to the forged products. The drawback is a result of the way the toggles and links which join them are borne. The links are mounted on the axes of the toggle joints, which increases the width of the device.
2. In order to disassemble even one toot holder, the longitudinal beams of the frame have to be disassembled.
3. The bearing plays of the links cannot be adjusted.
4. The force clamping the material in the dies is equal to half the press force. Such clamping system has the drawback that the material clamping force is a function of the upsetting resistance and, due to the changing inclination angle of the toggles during the working stroke, the value of the ratio of the clamping force to the upsetting resistance is also reduced. The largest forces moving the dies apart arise at the end of forming the product in the die impression. As a result of the force of the deformed metal in the die impression, the die expanding force can exceed the clamping one if this is the case, the transverse dimension of the workpiece increases and a gap between the die inserts in their parting plane is formed.
5. During upsetting, the deformed material moves together with the tool holder. The motion is complex along an arc path. When long rods are forged, this is a significant difficulty due to the inertia forces. Moreover, due to the quick movements of the upset material, the operator c cannot hold it, e.g. in tongs. This complicates handling of the rod when putting it to the subsequent die impression. The result is longer forging time, excessive heating of the tools and, consequently, deterioration of their durability.
6. When the tool holders are put together in the working stroke, they bump each other in the parting plane causing noise and undesirable stresses in some design nodes of the device, which can lead to its damage.
The objective of the invention is to eliminate those inconveniences. In accordance with the invention, the objective has been obtained thanks to the fact that each link has two separate bearing pins one of which is installed on the tool holder supported on the parallelogram linkage mechanism, the other is installed on the rigid structure on which the parallelogram linkage mechanism is supported.
Adjustability of one of the bearing pins is advisable.
In some cases, it is advantageous for the adjustable beating pin to be installed on the longitudinal beam of the frame.
In another alternative, it is advantageous to install the adjustable bearing pin on the head of the device.
It is advantageous, if the adjustable bearing pin is seated on an eccentric provided with position securing blockade.
In order to eliminate the undesirable vibration and noise, it is advisable to provide the tool holders with oblique bumpers facing the elastic ones located in one of the rigid structures.
As an alternative, elastic bumpers can be installed in the tool holder to face the oblique bumpers located in one of the rigid structures.
In order to prevent the split dies going apart during working stroke, it is advantageous, if the tool holder containing the die insert with the forming impression and supported on the parallelogram linkage mechanism, is slidably supported on a console, i.e. sole, perpendicular to the head motion and parallel to the upsetting direction, which console is rigidly connected to the oppositely working tool holder supported on the other parallelogram linkage mechanism.
In another possible solution, in order to prevent the split dies going apart during the working stroke, the tool holder supported on the parallelogram linkage mechanism, is slidably supported on at least one console perpendicular to the head motion and parallel to the upsetting direction which console is rigidly connected with a punch slider slidably seated on a guide parallel to the head motion.
It is advantageous, if at least one of its tool holders supported on the parallelogram linkage mechanism is provided with a die insert holder slider with which it is slidably connected in the direction perpendicular to the head motion and parallel to the upsetting direction, the die insert holder slider being immovable in the direction perpendicular to the head motion.
In another possible solution, the tool holder supported on the parallelogram linkage mechanism has a projection to couple it with a punch slider slidable in the direction perpendicular to the press slider motion.
Another design solution is possible, too, in which the tool holders supported on the parallelogram linkage mechanism situated on one side of the die parting plane are connected to those on the other side of the plane by means of columns arranged parallel to the direction of the head motion and the tool holders supported on the parallelogram linkage mechanisms are equipped with pulling back mechanisms.